A novel infrared laser system will be developed specifically designed for Dental hard tissue applications, namely prevention and conservative removal of Dental caries, while retaining the necessary hemostatic properties useful for soft tissue surgery. Preliminary experiments, support the hypothesis that lambda = 9.6 um laser light with pulse durations on the order of the thermal relaxation time of the deposited laser radiation (2 us) has excellent potential for realizing that objective. This hypothesis will be tested by the following specific aims: 1) to develop a short pulse CO2 laser operating at 9.6 um, that can be used effectively for Dental hard tissue applications, namely caries prevention and ablation; 2) to establish the irradiation conditions that minimize thermal and acoustic insult to peripheral healthy tissue while efficiently ablating and annealing Dental hard tissue; and 3) to use the above information to indicate laser conditions that can be tested clinically. This study will yield the specific laser parameters to be tested clinically for safety and efficacy in Phases II and III. If those clinical studies are a success, they will lead to the introduction of a novel lambda=9.6 um CO2 laser system that can be used effectively for most oral surgical procedures and is affordable to the dentist. PROPOSED COMMERCIAL APPLICATION: Laser ablation of dental caries, laser treatments for caries prevention, soft tissue oral surgery